ok. my setup:

S-FMU
415 cc/min injectors
walbro in-tank pump
HRC in-line "raped pig" pump

right after the rebuild, i put in the 2.72" S-FMU disk with the hard spring. too rich. i lost the other disks and rings so i dealt with it for a few weeks. i got fuel cut if i pushed more than 10 psi because the fuel pressure kept rising higher and higher. the A/F gauge was pinned all the way to the right.

friday night, the disks and rings turned up. i put in the next size down S-FMU disk. i think it's the 2.42" disk. not really sure. reset the ECU, drove around for a day to let it figure out life, and the A/F gauge is still pinned to the right when in open loop. i still get fuel cut above 10 psi because i'm running so rich.

today, i put in the smallest disk that comes with the kit, i think it's the 2.22" disk. still too rich, i still get fuel cut above 10 psi.

this week i'll order the bleed valve from Vortech and use the bleed screw to tune the fuel curves when i get to work on my car next, which will be on friday when i go home from college.

one thing that confuses me is that when i'm at part throttle, and in closed loop mode, when i go into boost the A/F gauge goes into the red, and stays there. it's been doing this regardless of the disk i have in the S-FMU. if i stay long enough at x psi it will start to go back and forth like it should. it's like the computer is programmed to:

1. if the driver is less than 80% throttle and is increacing throttle posistion while intake manifold pressure is greater or equal to 0 psi, make the mixture unacceptablally lean.
2. if the driver leaves the throttle at one posistion while intake manifold pressure is greater or equal to 0 psi, leave it unacceptably lean for 3-5 seconds then start cycling the mixture like any other normal closed-loop computer would do.
3. if the driver is decreacing the throttle level in closed loop mode, dump gas into the engine and make the a/f gauge go all the way into the green.

my MAP voltages never really go above 4.1 volts according to the S-AFC (i do NOT have any correction programmed in at all). i still have the HRC black box there along with the missing link because with the missing link alone i get fuel cut only at exactly 0 psi. doesn't the computer automatically go into open loop mode if the pressure is equal to 0 psi (WOT in a N/A car) which is 4.5 volts? we get fuel cut if the voltage approaches 5 volts, right?

seems pretty backwards to me.


i KNOW i have enough fuel pressure, because if i bring it to WOT and open loop mode at that boost level it goes right into the green. i'm just worried because it's in the red and i'm boosting upwards of 10 psi. i saw it happening (approaching 10 psi and the a/f gauge was still in the red, while in closed loop mode), and i let off the gas (from part throttle) that only happened once, i let off and was kind of worried about detonation so i went home and did a compression check and got about 180 across all 4 cylinders which is pretty ideal for 8.6:1 pistons.

sorry about the long post. probably the longest one i've ever made. anyone offer any advice? thanks.

bump... come on guys, need some help here.

Ok, first question- what is your idle fuel pressure? and what are your boosted fuel pressures at 10 psi? That aside..

A A/F gauge will only be accurate in open loop. This is at anything over approx 80% throttle. This is when the A/F gauge will show your true state of tune. When part throttle boosting, your o2 sensor is trying to keep your A/F mixture "stoichiometric", which is what the ECU is programmed for, to get the best gas miliage, and A/F ratio. Now the ECU does not know that there is a turbo on there, so it retains the stock fuel map, and what the A/F should be for a NA motor. This is usually fine for lower boost, as you can get away with it without any detonation on stock compression ratio. You having lower compression, gives you more headroom to run that 10 psi in closed loop mode, wihtout any detonation. I'd say thats the limit thogh. The point at which you can build 10psi without using more than 80% throttle is prob at the max right now anyway, so i woulndt worry about that, as you can do nothing to change your A/F ratio in closed loop boost other than adjust your SAFC. Its strange that you run really rich with the smallest SFMU disk in, but you may be running to much idle fuel pressure, which is giving you too much fuel. The bleed valve will be of great help there. Also, what are your EGT's at 10 psi? That will tell you the most of anything, if you are runnign too rich or lean. You want EGT's to be around 1550-1575 at WOT full boost.
And another thing:
TAKE OFF THE HRC BLACK BOX!!! That thing is junk IMO. It clamps your map at the wrong voltage causing problems. You want your MAP volts to be at 4.5 volts at 0 psi. You can test this with the car off, and the key in the run positon,and see what your SAFC reads. Then take off the HRC FCD, and then see what it reads. I'd bet your MAP voltage will be a little higher :)

yeah, my idle pressure with the 415's is about 20 psi. i bet this is kind of high. my passanger said that my fuel pressure at 10 psi of boost was 55 psi of fuel with the 2.22" disk, but sometimes he can't get anything right and it's hard to see the fuel pressure gauge from the driver's seat without hitting things. at WOT, the A/F gauge is almost pinned to the right. so i guess i'll have to have a more competient co-pilot.

and yeah, i'm not very confortable with the HRC black box. taking it off would be a really good idea.

about closed loop in boost, i've never been very comfortable with that either. i've been cooking up a few ideas on how to solve that problem though... http://129.63.64.48:443/EE.txt